Ingredients
2 large onions, chopped
4 medium carrots, sliced
2 cups chopped celery
2 green bell peppers, chopped
18 to 20 large tomatoes
1/4 cup olive oil
2 teaspoons salt, or to taste

Procedure
Sauté onion, carrots, celery and green peppers in olive oil until onions are limp and transparent. Peel, core and chop tomatoes (you should have 4 quarts). Add to vegetables and cook about 15 minutes.

Purée vegetables in a food processor, press through a fine sieve, or put through a food mill. Add salt and cook sauce, uncovered, until thick (about 1 hour), stirring frequently to prevent sticking. The final consistency should fall halfway between juice and paste.

Quickly ladle into clean, hot jars, leaving 1/2-inch headspace; seal. Process in boiling water bath 45 minutes.

Yields about 4 to 5 pints.